the bombings.presidentobamamarkedthe moment of silence from the white house. the u.s. senate held a similar tribute on capitol hill. it is still unclear what impact the boston bombings will have on the immigration debate in congress. but the topic of national security is clearly playing a more prominent role in the discussion. things got tense on capitol hill yesterday when senator chuck schumer sparred republican senator chuck grassley about the future of the legislation. take a look. >> a few ways to improve the bill all for an amendment when we start mark-up in may and let's vote on it. i say that particularly those who were pointing to what happened. the terrible tragedy in boston as a -- i would say an excuse for not doing a bill or delaying it many months oer years. >> i never said that. >> i didn't say you did, sir. >> i didn't say -- >> i didn't say you did. i don't mean you, mr. grassley. >> mr. chairman, i don't appreciate the senator demeaning the witnesses that have come here. >> earlier, senator patrick leahy who chairs the judiciary committee opened the hearing with some tough

conferencepresidentobamaspokefrom the white house. >> good evening, everybody. tonight our nation is in debt to the people of boston and the people of massachusetts. after a vicious attack on their city the people of boston responded with resolve and determinations. they did their part as citizens and partners in the investigation. boston police, state police, and local police responded with professionalism and bravery over five long days. tonight, because of their determined efforts we've closed an important chapter in this tragedy. i've been briefed earlier this evening after the attacks on monday, i directed the full resources of the federal government to be made available to help state, local authorities in the investigation and to increase security as needed. over the past week, close coordination over state and local officials to track down leads has been critical to this effort. they all work as they should, as a team. we are extremely grateful for that. we o'a tremendous debt of gratitude to all of our law enforcement professionals. these men and women get up every day an

to speak is governor deval patrick as well aspresidentobamawhowill speak at the end of the service and will bring those remarks to you live. as you know in any sort of in terms of healing it, the key is willing a will to heal. that is very much apparent here in boston. now onto the investigation, as carl said two individuals being sought by authorities on camera, videos can be waptured of these individuals around the time of the bombing, but authorities are also saying that the pictures of those individuals have not been released. so pictures are not the men that authorities are looking for. but there were multiple images that captured the explosion and the time leading up to it. that's what authorities are looking at frame by frame by frame. not just cell phone video, but surveillance video. we talked about the lord & taylor camera directly across the street from the second bombing. there were two other cameras at least that were supplied by a company called access communications. those cameras were high definition cameras. so these could be very high quality images, and we expect